1. Field of the Invention
The present invention relates to a mechanism for setting a cartridge having a tape reel housed therein, more particularly to a mechanism for setting a magnetic tape cartridge in a magnetic tape device.
2. Description of the Related Art
FIG. 1 is an exploded view in perspective of a magnetic tape cartridge setting mechanism of a conventional type described in Japanese Patent Laid-open 226465/1987.
In FIG. 1, housing driving plate 2 is provided on base plate 1 in a slidable manner, having linear standing plates 3, 3 (only standing plate 3 in one side is shown) of a long and narrow shape parallelly provided on both sides thereof. A pair of guide plates 4, 4 of the same shape are vertically provided on standing plates 3, 3, respectively, being horizontally spaced to each other. Both guide plates 4, 4 have guide grooves 5, 5 of the same shape formed in the same direction, respectively. FIG. 2 is a side elevation showing one guide plate 4 and its surroundings, where each guide groove 5 is composed of a horizontal part at the top thereof and inclined surfaces extending obliquely downwardly.
Above housing driving plate 2, there is provided housing 9 of a flat and approximately square shape with a downwardly open almost U-shaped section disposed in such a manner that openings 10 A and 10 B in respective ends thereof are situated in the longitudinal direction of said base plate 1. On each of both side walls 11, 11 of this housing 9, a pair of pins 12, 12 (only pins 12, 12 on one side wall 11 are shown) are provided being projected therefrom and horizontally spaced to each other, where the distance between both pins 12, 12 is equal to the distance between both guide plates 4, 4 provided on one standing plate 3. Pin 12 is supported by guide groove 5 and housing 9 is guided so that it can be moved in the vertical direction by means of a guide member which is not shown here.
Support plate 13 is provided inside each side wall 11 of housing 9 in the horizontal direction at the lower end thereof. Housing 9 has a shape almost similar with the shape of tape cartridge 14, and hence by preparing housing 9 such that both ends of tape cartridge 14 are supported on both support plates 13, 13, housing 9 can contain and hold tape cartridge 14.
In opening 34 formed in the central part of housing driving plate 2, there is face gear (end surface gear in a form of a crown gear) 36 to be driven by motor 35 which is vertically provided on base plate 1. Opening 34 is formed being sufficiently spaced from face gear 36 so that face gear 36 may not hinder movement of housing driving plate 2.
In tape reel 38 provided inside tape cartridge 14 which is to be inserted into housing 9 from opening 10 A, there is attached face gear 40 with gear teeth formed downwards. Face gear 40 engages with face gear 36 thereby transmitting the drive of motor 35 to tape reel 38.
On base plate 1, stationary cam 43 of a plate form is provided in such a manner that it is supported by a plurality of props 42, 42 . . . , rotation shaft 46 is provided on said stationary cam 43 in the rotatable relationship, and a first disk 47 and a second disk 48 are fitted to rotation shaft 46 so that they can slide accompanying the rotation of rotation shaft 46, respectively. Motor 49 vertically provided on base plate 1 rotates rotation shaft 46 through spur gears 51, 52 attached to rotation shaft 50 of motor 49.
FIG. 3 is a plan view showing disks 47, 48 and surroundings thereof.
Cam groove 53 of almost a spiral shape is formed in first disk 47.
Lever 55 is provided in such a manner that it is rotatably movable around support shaft 54 vertically provided on base plate 1 and substantially along the direction of movement of housing driving plate 2. Pin 56 projectingly provided at the tip of lever 55 engages with cam groove 53 of first disk 47 and pin 58 projectingly provided on the end of housing driving plate 2 engages with long hole 57 formed in lever 55. First ejection middle lever 59 is set on rotation shaft 50 so as to be rotatable independent of the movement of rotation shaft 50, and arm 61 of lever 59 extending toward first disk 47 pressure contacts with pin 62 projectingly provided on first disk 47 being influenced by the effect of spring 60. Ejection lever 66 is provided in a rotatable manner centering support 65 which is vertically provided on base plate 1, with the tip of eject lever 66 which enters housing 9 through opening 10 B of housing 9. Pin 71 provided at the tip of second ejection middle lever 69 set on support 68 provided on ejection lever 66 pressure contacts with first ejection middle lever 59 through the effect of spring 70.
FIG. 3 shows an initial state in which tape cartridge 14 is not yet inserted into housing 9. In this state, pin 56 of lever 55 is located in the outermost circumference side of cam groove 53 formed in first disk 47. First ejection middle lever 59 is pushed by pin 62 of first disk 47 to turn counterclockwise, pin 71 of second ejection middle lever 69 abuts on the rear of stepped part 64 of first ejection middle lever 59, and ejection lever 66 shunts out of housing 9 due to the function of spring 67.
In these circumstances, in order to record/read information on or from a tape of tape cartridge 14 with this magnetic tape device, it is required to first push a start button not shown. Then, motor 49 is driven to turn rotation shaft 46 counterclockwise, concurrently causing first disk 47 united with rotation shaft 46 to turn also counterclockwise. With the rotation of this first disk 47, first ejection middle lever 59 which is in contact with pin 62 is rotated clockwise under the influence of spring 60 and concurrently pin 56 of lever 55 which is in engagement with cam groove 53 moves toward the center of first disk 47 thereby turning lever 55 counterclockwise to make housing driving plate 2 move in the left direction in FIG. 1. In the initial state of this housing driving plate 2, as shown in FIG. 2, each pin 12 of housing 9 fitted in guide groove 5 of each guide plate 4 is located at the outer end of a horizontal part in the upper end of guide groove 5. When this housing driving plate 2 moves in the left direction in FIG. 2, door 16 (being energized toward the closing direction of spring 17) provided at opening 10 A of housing 9 is turned around support 15 (which is fixed to housing 9) to open by the function of lever 20 which has pin 23 attached to support shaft 21 provided on base plate 1 and cam 8 provided on housing driving plate 2.
With door 16 held open, tape cartridge 14 is inserted into housing 9 through opening 10 A. When the insertion of tape cartridge 14 is detected by such as a limit switch, motor 49 is driven again to turn first disk 47 anticlockwise, and accordingly pin 56 moves along cam groove 53 further toward the center direction of first disk 47 thereby turning lever 55 counterclockwise and making housing driving plate 2 shift in the left direction. Consequently, each pin 12 goes down along the inclined surface of each guide groove 5, thereby causing housing 9 to go down and resultantly making face gear 40 of tape cartridge 14 engage with face gear 36.
Also, accompanying the rotation of second disk 48 which is generated being driven by motor 49, leader block 39 attached to the initial tape at the top of tape cartridge 14 is drawn out of tape cartridge 14 and drawn around so that the tape contacts magnetic head 44 on base plate 1 and then attached to winding reel 94 which is to be driven by motor 95 vertically provided on base plate 1, owing to the operation of the following items such as first driving arm 76 fitted to rotation shaft 46, second driving arm 81 set on support 80 provided on first driving arm 76 while having pin 84 which moves along the cam surface of stationary cam 43, driving lever 90 which is fitted to hold pin 32 provided on second driving arm 81 and on support 89 which is stationary with reference to base plate 1 while having pin 91 which contacts the cam surface 73 of second disk 48.
After finishing recording/reading of the tape using magnetic head 44 and winding the tape again by tape reel 38, motor 49 is driven to turn first disk 47 clockwise. Accordingly, pin 56 begins to move cam groove 53 of first disk 47, lever 55 turns clockwise causing housing driving plate 2 to move in the right direction in FIG. 1, each pin 12 goes upward along the inclined part of each guide groove 5 and housing 9 also ascends to release engagement between face gears 40 and 36. When each pin 12 reaches the uppermost end of guide groove 5, ascending of housing 9 is stopped and then door 16 is opened by the operation of lever 20. pin 23 and cam 8.
While, when housing 9 reaches the uppermost ascended position, first ejection middle lever 59 is pushed by pin 62 projectingly provided on first disk 47 and turns counterclockwise. Then, since pin 71 of second ejection middle lever 69 is engaged with stepped part 64 of first ejection middle lever 59, this second ejection middle lever 69 is moved in the substantially longitudinal direction because of the anticlockwise turn of first ejection middle lever 59, and ejection lever 66 is turned clockwise against the force of spring 67, and hence tape cartridge 14 in housing 9 is pushed by ejection lever 66 to be pushed out through opening 10 A which is held open.
In the conventional technique described above, the setting speed and the discharging speed of cartridges are dispersed in a wide range without converging to some fixed value, thus having a problem that the setting and the discharging motion of cartridges remain unstable. For example, in some case, a cartridge is suddenly discharged and hence it is difficult to push out only the front edge of the cartridge from the housing (cartridge tray) but the whole cartridge is rushed out causing the cartridge to drop down straight, or in another case, the cartridge discharge operation is not finished within an allowable limit of time judged from the viewpoint of design.
The reason of the above is that the conventional technique has a complicated structure in which many cams, links and springs are used, in other words, because of the dispersion in dimensions of various parts, the dispersion of various spring force and the influence of various friction, the operation speed of ejection lever for discharging cartridges or the upward and downward motion speed of the housing vary in a wide range.